This invention relates to the feeding of cigarette filters comprised of fiber, charcoal, or various combinations thereof to a cigarette making machine. More particularly this invention relates to the feeding of fragile filter elements such as charcoal filters to a cigarette making machine. Even more particularly this invention relates to the agitation of a cigarette filter hopper in the feeding of charcoal filters to a cigarette making machine.
The cigarette manufacturing industry utilizes automated machines to interconnect cigarette filter rods with tobacco rods. One method of joining the cigarette rods to the filters is by using a filter tip attachment machine by aligning the distal ends of a single filter rod with a pair of tobacco rods, wrapping the joint with tipping paper, and cutting the filter in the center forming two cigarettes.
In the manufacture of filter tip cigarettes prior to the feeding of filter rods into a filter tip attachment machine, a filter hopper is provided to store cigarette filters and is a source of supply for the filters when the filter attaching machine is operating. Moreover, in order to maintain a uniform supply of these filters into the feed end of a filter attachment machine, bins have been provided to maintain the agitation of the cigarette filters in the feed hopper so that uniformity of feed to the filter attaching machine is maintained. For example, U.S. Pat. Nos. 3,081,778 and 3,308,833 teach the use of an oscillating agitating flap mounted within the feed hopper which prevents the weight of the bulk of filters in the hopper to press on the region where the filters are discharged and also tends to break up the bridging of the filters over the discharge. U.S. Pat. No. 4,069,930 teaches a feed hopper including an agitator translatable in the hopper; and U.S. Pat. No. 4,063,633 teaches an agitator disposed within the hopper which is mounted to rotate or oscillate in order to break up clumps of rods which may form in the hopper.
Moreover, it has been known to employ a cam mechanism to the frame of a feed hopper or directly to the feed hopper wherein the cam oscillates the hopper in response to the operation of the mechanism for discharging the filter rods from the filter hopper.
Because of variations in the rate of production, the filter feed conveying equipment and hopper agitating equipment is routinely stopped and started for various reasons, such as when the quantity of filters exceeds a predetermined amount in the hopper due to a faster rate of supply than demand with the filter attachment machine. Since the supply of filter rods may be from a conveyor mechanism located several feet from the filter attachment machine, the number of rods in transit at any instant may be considerable. Thus, where the supply unit is stopped in response to a command from the filter tip attachment machine all of the filter rods in transit will continue to be delivered to the hopper which has been stopped from delivery of filters to the attachment machine.
Typically, these devices are adequate for feeding cigarette filters including a porous fiber filter element attached to the cigarette such as shown and described in U.S. Pat. No. 4,498,488. However, carbon filled cigarette filters generally tend to be heavier, yet more fragile than porous fiber filter elements. Because charcoal filters are made in segments they tend to break when fed using conventional hopper feeding apparatus.
When charcoal filters are fed to the hopper via a pneumatic conveyor system after the agitator and hopper feed mechanism have been turned off due to a problem with the cigarette attachment machine, the charcoal filters will tear because of the extra pressure of the heavier "charcoal" filters already in the hopper. Also, the filter wrap for charcoal have a much higher friction ratio than standard filter wrap. Because the charcoal filters are made in segments the filters tend to tear and break during the feed process to conventional hopper filter dispensing system, when the filter attachment machine stops running because the conventional agitator systems are designed to stop running at the same time the filters are still being fed to the hopper through the pneumatic conveying system. Furthermore, when the agitator is not running the excessive weight from the charcoal filters cause the filters to lock up and jam the hopper instead of sliding across each other. Thus, the existing operation of conventional agitators presents a problem when feeding charcoal filters pneumatically.
The filter vibratory devices described in the aforementioned references are designed to utilize existing gear drive means and to run only in the event the filter attachment machine is running in order not to overfill the cigarette filter hopper. These agitating devices perform adequately using standard light weight, one piece, fibrous cigarette filters. However, pneumatic feeding of fragile, heavier, segmented charcoal filters by these aforementioned devices presents a problem in that the agitators tend to damage and tear apart the carbon filled filter elements resulting in jamming of the hopper feed mechanism, lost time, increased maintenance, and damaged material.
The present invention solves the problems associated with the agitation of fragile filters by providing a novel means to maintain a consistent flow of carbon filled filters through the feed hopper to the filter attachment machine regardless of the density or material of construction of the filter elements. The system allows the filter elements to move up and down and side to side within the hopper more freely without binding and allows more room for the incoming filters from the receiver. Moreover, the present invention utilizes a means to agitate the filter elements even when the filter attachment machine is not operating, but is still receiving filters from the pneumatic filter conveyors.